Dipstick screening for urinary tract infection.

In screening for urinary tract infection the leucocyte esterase test will detect almost all samples with significant pyuria and bacteriuria, but is relatively nonspecific. The nitrite test is more specific but less sensitive and about one-third of the urinary tract infections in a large group of children were missed. The combination of screening tests results in greater overall accuracy both in the diagnosis and exclusion of urinary tract infection. Almost all cases of urinary tract infection were detected when either the leucocyte esterase or the nitrite screening test or both were positive. If both tests are negative, urinary tract infection is virtually excluded and unless the child is symptomatic, further urinalysis is unnecessary. Laboratory urinalysis is, however, necessary if any one screening test for leucocyte esterase or nitrite (or protein or haemoglobin) is positive. Combined biochemical screening for urinary tract infection with dipstick test strips is reliable and allows early diagnosis and management. By avoiding unnecessary urinalysis it is cost-effective for the patient and will significantly reduce the laboratory workload.